"Good morning to you, good morning to you," Mary Mears, a pre-K teacher, sang to her 24 students at Greenbelt Elementary School one recent morning. She held a stuffed tiger in her lap and gently asked the children to keep their eyes on it. "Today is a brand-new day with no mistakes in it," she repeated several times.

The children paid attention, for the most part. Through the eyes of 4- and 5-year-olds, the world is full of distractions: There are the colorful walls, sprinkled with pictures and unfamiliar words; their classmates, behaving in unexpected ways; even their own bodies, which they are just learning to control.

Mears shook out a little bit of their energy by telling the youngsters to stretch and run in place. Then she told them something that was sure to get them excited.

"Guess what?" she said. "We are going to be going to the firetruck today!" (A truck was parked at the school for Career Day.)

The kids clapped and cheered. "Yessss!" one boy cried.

They were so pumped up that Mears seemed worried they wouldn't be able to handle the next exercise. "We're not going to get carried away, right?" she asked. The students didn't make any promises. Mears played a song, to the tune of "Buffalo Gals." The next few minutes illustrated the proverb that everything you really need to know you learn in kindergarten, or in this case pre-K:

"Everybody shake a hand, shake a hand, shake a hand,

Everybody shake a hand and walk around the room . . . "

(This skill is useful in many situations, including politics, parties and job interviews.)